Gloom's branchedevolution family as demonstrated in the anime: both of Gloom's potential evolutions require an evolutionary stone.

An evolutionary stone (Japanese: 進化の石Evolution stone) is a stone-like item that radiates a mysterious energy that causes some species of Pokémon to evolve.

Another stone, the Everstone, is different in that it radiates a type of energy that prevents Evolution in the holders; however, if a Pokémon holding the Everstone has an evolutionary stone used on it, it will still evolve.

Evolutionary stones may be used at any time, and cause instant Evolution in the Pokémon they are used on, which cannot be canceled. With the exception of the Everstone, which must be held for its effects to take place, all evolutionary stones are applied directly to the Pokémon. All stones that cause Evolution in a Pokémon are consumed upon that Pokémon's evolution.

Many Pokémon that result from a stone-based evolution have vastly different level-up learnsets than their pre-evolutionary forms, with several learning no moves after Evolution at all.

If held in the Pokémon Day Care by a female Pokémon or Ditto, Pokémon bred will have a 50% chance of having the nature of the holder.EDPPtIf held in the Pokémon Day Care by either parent, Pokémon bred will have a 50% chance of having the nature of the holder.HGSSBWIf held in the Pokémon Day Care by either parent, Pokémon bred will definitely have the nature of the holder.B2W2XY

An item to be held by a Pokémon. A Pokémon holding this peculiar stone is prevented from evolving.

In the anime

A giant Moon Stone

Evolutionary stones are showcased somewhat rarely in the anime, as only a relative few Pokémon are able to evolve by using them. Despite this, they were among the earliest of items to have been showcased in the anime, appearing as early as Clefairy and the Moon Stone, where a rather large Moon Stone appeared deep within Mt. Moon. It was being worshipped by a group of Clefairy who lived there, and was soon stolen by Team Rocket and ended up being blown up. The shards from it, however, rained down on the Clefairy and caused some of them to evolve into Clefable. It is also speculated in the anime that the Moon Stone was the reason why and how various Pokémon—Clefairy in particular—arrived in the Pokémon world.

The second appearance of an evolutionary stone occurred in Electric Shock Showdown, where the Thunder Stone was introduced. This was likewise the first opportunity that a Pokémon belonging to a main character was given to evolve by stone. Ash's Pikachu, however, refused the offer, intending to beat Lt. Surge's Raichu as a Pikachu. He kept the Thunder Stone on hand, in case Pikachu ever wanted to evolve; however, in Pika and Goliath!, the same scenario occurred and Pikachu still refused to evolve. Seeing his determination of not evolving, Team Rocket stole it, planning to sell it.

A forest that appeared in The March of the Exeggutor Squad, was a reported hotbed of Leaf Stones, and the radiation from these stones in the forest was so strong as to induce Evolution in Melvin's Exeggcute, which proceeded to cause chaos by hypnotizing a horde of other Exeggutor.

A fake Leaf Stone, made by Team Rocket, appeared in Make Room for Gloom, where the discovery of its nature as a fake was central to the episode.

Ursula used a Fire Stone and a Water Stone to evolve her two Eevee in Last Call, First Round!, making them a Flareon and Vaporeon, for use in the Grand Festival.

Ash had to find a Thunder Stone as part of a scavenger hunt in Climbing the Tower of Success!. He came across a young man in possession of one who tried to toss it to him from a long distance. The Thunder Stone nearly came in contact with Pikachu but he jumped out of the way just in time leaving Ash to catch it.

A Thunder Stone appeared in To Catch a Pokémon Smuggler! as a part of Clemont's explanation of how Pokémon Evolution works, Pikachu's evolution into Raichu working as an example of stone-induced Evolution.

A full set of evolutionary stones was seen on display in a stone shop in Geosenge Town in The Cave of Trials!. In addition, an unnamed Trainer used a Sun Stone bought from the shop to evolve his Helioptile into Heliolisk. Clemont then revealed that he had also used a Sun Stone to evolve his own Helioptile into Heliolisk.

Evolutionary stones do not seem to be required for evolution in the anime as they are in the games. James's second Weepinbell evolved without a Leaf Stone in Here's Lookin' at You, Elekid, though this may just be an example of anime physics. In addition, Pokémon that evolve via proximity of evolutionary stones apparently seem to control their evolutionary urges and physically touch the stone without evolving, as evidenced by Pikachu whacking away the Thunder Stone when refusing to evolve the first time, as well as a Clefairy holding onto a Moon Stone for prolonged periods of time before delivering it to the larger Moon Stone without evolving.

She is later given a Water Stone by Mikey, who is being pressured to join the "Knights of the E Stone", a club which requires members to own a Pokémon evolved by an evolutionary stone. By battling club members, Ash and Mikey prove to the leaders that Pokémon which have evolved by evolutionary stone are not necessarily superior to their unevolved counterparts.

In the TCG

The Moon Stone and Dusk Stone are featured in the Pokémon Trading Card Game on a Trainer card and on Pokémon cards as held items. These held items work in the same fashion as Poké-Bodies, in that the effect the item provides is active whenever the Pokémon is in play. The following is a list of cards named or including Moon Stone or Dusk Stone.

Evolutionary stone cardsCards listed with a blue background are only legal to use in the current Expanded format.Cards listed with a silver background are legal to use in both the current Standard and Expanded formats.

Simisage is the only Pokémon evolved via Leaf Stone which is not dual-typed.

The Oval Stone is sometimes considered an evolutionary stone, and can even be selected to be used like one. However, unlike other evolutionary stones, the Oval Stone does not trigger Evolution in any Pokémon when it is used on them. It must instead be held and the Pokémon leveled up, making it an evolution-inducing held item.

Through a glitch in the Generation I games, Pokémon can be evolved without the use of a stone, provided that the player has sent out the correct Pokémon in the same battle that a Pokémon that evolves using a stone levels up.

The Dawn Stone induces Evolution in only two Pokémon species, Kirlia and Snorunt, the fewest of any stone. Both of them only work if the Pokémon is of a specific gender.

This also makes it currently the only stone that only evolves Pokémon introduced in a single generation, as Kirlia and Snorunt were both introduced in Generation III, likewise, their evolutions were both introduced in Generation IV.